# How can I determine pressure leakage in a pneumatic system?

I am an engineer currently designing a system in which the leakage of a hose is tested. The system consists of the following components:

1. An air data system used to generate a pressure inside the hose.
2. An automated pressure measurement device used to measure the pressure in the hose.

The goal of the test is for the air data system to exert a pressure on the hose and make sure that the pressure doesn't drop while the system maintains that pressure. The air data system will maintain the pressure and the measurement device will periodically read the pressure over a length of time. After some time has passed there is a limit to which the pressure should have changed. If that limit is exceeded the test will be considered a failure otherwise considered a pass.

The pressure measurement device is not perfect and leaks a small amount of pressure on its own. Is there a way to account for how much pressure is leaked by the pressure measurement device? I'd like to do this in order to get a slightly more accurate value for pressure in the hose.

If it helps, here is some other information I know about the system:

1. The air data system is +/- 2% accurate.
2. The air data system can be detached from the pressure measurement device and measure its own pressure it's putting out.

Is there a way where maybe I can measure the pressure of the air data system in isolation, and then with the pressure measurement device attached... in order to maybe obtain some sort of mathematical/physical relationship or system of equations? I am thinking that something along those lines might work.

• I only just deleted this from physics like 3 minutes ago and pasted it here instead, in-case it looks like a cross-post. Oct 26, 2017 at 14:18

## 1 Answer

Fit a dummy test hose with no leaks - a solid tube for example, then pressurise the system to a known value perhaps the maximum used +10%.

Then take readings every 10 seconds / 5 minutes (whatever is relevant for your real tests) for a defined amount of time ie 10* the length of a normal test. Repeat 10 times.

Average the results for the "loss per unit time" of the standard system parts.

Test a real hose and see if the results deviate form the known leak curve... If they do you have a leak and its severity...